Tzima E, Martin C J
Department of Bio-Medical Physics and Bio-engineering, University of Aberdeen, UK.
Physiol Meas. 1994 May;15(2):201-16. doi: 10.1088/0967-3334/15/2/008.
Stray electric and magnetic fields have been measured near to therapeutic and surgical diathermy equipment for many different treatments. The highest field strengths are associated with continuous wave (cw) 27 MHz therapeutic diathermy equipment for which fields above national reference levels extend for 1 m from the electrodes and cables. The extent of the fields does not vary substantially with the type of treatment being performed. Recommendations that operators remain 1.0 m from cw therapeutic diathermy equipment, 0.5-0.8 m from pulsed treatments with capacitive electrodes and 0.2 m from pulsed inductive applicators can be applied to restrict exposure for any treatment with each type of unit. In a proposed European Community (EC) directive, action levels similar in magnitude to the reference levels are used to trigger requirements for assessments of hazard, measures to reduce exposure and personnel training. Assessments and appropriate recommendations of measures to reduce exposure can be linked to the type of equipment. Fields associated with electrosurgical units operating at frequencies of 0.3-0.5 MHz only approached reference levels within 20-30 cm of the cables, and because of the relatively short durations of the emissions, precautions were considered unnecessary with the units tested.
在用于多种不同治疗的治疗性和外科透热设备附近，已测量到杂散电场和磁场。最高场强与连续波（cw）27 MHz治疗性透热设备相关，对于该设备，超过国家参考水平的场从电极和电缆延伸1米。场的范围不会因所进行的治疗类型而有很大变化。建议操作人员与连续波治疗性透热设备保持1.0米的距离，与使用电容性电极的脉冲治疗保持0.5 - 0.8米的距离，与脉冲感应施加器保持0.2米的距离，这些建议可用于限制每种类型设备进行任何治疗时的暴露。在拟议的欧洲共同体（EC）指令中，与参考水平大小相似的行动水平用于触发危害评估、减少暴露措施和人员培训的要求。减少暴露措施的评估和适当建议可与设备类型相关联。在频率为0.3 - 0.5 MHz运行的电外科设备所产生的场仅在电缆20 - 30厘米范围内接近参考水平，并且由于发射持续时间相对较短，对于所测试的设备，认为无需采取预防措施。
